Nailbed Injuries Treatment & Management

Subungual hematoma

• Small and painless subungual hematomas require no treatment, as blood will be incorporated into the surrounding tissues and eventually be removed with the free edge. If the subungual hematoma covers more than 25% of the nailbed or is causing pain it should be evacuated via trephination (see Hand, Subungual Hematoma Drainage).
• The treatment of subungual hematomas covering greater than 25-50% of the nailbed is controversial. The standard of care has been to remove the nail and repair any underlying laceration because 50% of hematomas have significant nail bed lacerations. The incidence increases to 94% when associated with distal phalangeal fracture, regardless of the size of the hematoma.
• Recent studies have concluded that as long as the nail is still partially adherent to the nailbed or paronychia and is not displaced out of the nail fold, removal of the nail and repair of the nailbed does not improve outcome versus simple trephination. No correlation was found between adverse outcome and the size of the hematoma or presence of an associated fracture.^{[8, 7, 9]}
• The advantages of simple trephination alone are less pain for the patient, shorter length of stay, and less costly intervention.^[7]

Evacuation of hematomas

• Various methods of trephination exist (shown in the image below). The easiest and safest is to use an electric cautery, which melts a hole through the nail. Once the cautery encounters the underlying hematoma, the tip cools, preventing further injury to the nailbed. If the hole is of adequate size, blood will drain and relieve some pain and the pressure sensation for the patient. Trephination of a subungual hematoma.
• A paper clip may also be used after it is heated until red hot.
• Use of an 18-gauge needle is less optimal because of the risk of injury to the nailbed once the nail has been penetrated.
• An alternative technique is use of a sterile 29-gauge extra-fine insulin syringe needle.^[10] Instead of penetrating the nail, the needle is inserted at the hyponychium parallel to the nail, aimed at the most distal portion of the hematoma. Care is taken to keep the needle closer to the nail versus the nail bed. Once the hematoma is penetrated, the needle may be withdrawn and light pressure placed on the nail will help with evacuation of the hematoma. This technique may obviate the need for digital block anesthesia, and also may be favorable in evacuating hematomas of the smaller toe nailbeds, where trephination is more difficult.

Nailbed repair

Principles of treatment include minimal debridement, preservation of as much tissue as possible, atraumatic wound care, and splinting with the nail or an alternative material. Nailbed repair is shown in the image below.

• A digital block of 1% lidocaine hydrochloride without epinephrine provides anesthesia of sufficient duration for most repairs. Bupivacaine extends anesthesia time 4-8 hours for longer procedures. A metacarpal or an axillary block may be used for multiple nailbed injuries.
• Children may require conscious sedation.
• The hand should be prepared with povidone-iodine (Betadine) and covered with sterile drapes. The injured finger should be exsanguinated with a half-inch or 1-inch Penrose drain wrapped in a distal to proximal direction and placed around the base to serve as a tourniquet and provide a blood-free field.
• The nail is elevated using the blades of either fine or curved iris scissors or small elevator scissors. Specific care is necessary to not injure the nailbed. A blunt dissecting technique should be used, and the scissors are placed gently underneath the nail until they reach the nail fold. Slowly open the scissors as it is removed. Care must again be taken to avoid further damage to the underlying nailbed or overlying nail fold. Once the nail is sufficiently separated from the nailbed, it is gently removed by applying firm and steady distal traction using a hemostat.
• Lacerations to the nailbed should be repaired using 6-0 or smaller absorbable sutures. Minimal to no debridement should be performed because aggressive debridement may cause undue tension on the repair and results in scarring.
• When repairing avulsed nails and nailbeds, if the nail is detached proximally, it must be removed to inspect for any damage to the nailbed. Careful inspection of the nail is important because often only a fragment of nailbed may be attached to the undersurface of the avulsed nail. Only outer and dorsal surfaces of the nail should be cleaned. Any large fragments of nailbed should be preserved for use as a free graft. Crushing injuries leave many small pieces of nailbed. If all fragments are not incorporated into the repair, they may grow independently and cause nail horns or spicules. If tissue is not available and the defect is small enough, the area will heal effectively by secondary intention.
• Simple dorsal roof lacerations can often be repaired by accurately repairing the skin overlying the nail fold. However, if possible, suturing of the dorsal roof with a 7-0 chromic suture may provide more accurate repair. Associated paronychial injuries must be repaired and stented to prevent pterygium or adhesions, as it serves as a mold to coax nail to grow along a proper path. Distal phalangeal fracture reduction and healing is important to final nail formation. Poor reduction of the bone translates directly into irregularities of the nailbed.
• A small hole should be made in the nail, preferably so that it is not overlying the laceration, to allow drainage and thus prevent a growing hematoma to separate the nail from the nailbed.
• The nail is then placed back in the nail fold as a stent and held in position by 5-0 or smaller nylon sutures placed by one of the techniques below:

  • Distally through the hyponychium and the nail
  • Through the nail and proximal to the nail fold^[11]
  • Through a half-buried horizontal mattress suture placed down proximal to the nail fold into proximal nail then back out the nail fold
  • Through the paronychia and nail bilaterally
  • As a dorsal figure-of-eight suture^[12] - A suture is placed transversely just distal to the hyponychium then placed proximal to the nail fold in the same direction and tied back to itself. If the nail slips laterally, 2 small vertical cuts may be made in the nail for the suture to catch upon.
• The use of tissue adhesives such as Indermil (n- butyl cyanoacrylate) or Dermabond (octyl-2-cyanoacrylate) is a less invasive option for nailbed and nail repair.^{[13, 14, 15, 16]}

  • Nail fragments may be repaired together first using adhesive, then secured into the nail fold by a thin layer placed under the nail, using gentle downward pressure while the adhesive dries.
  • Alternatively, nail fragments may be pieced together on the nailbed, with a light coating of adhesive wiped or dripped between adjoining fragments and on skin adjacent to the perimeter of the nail. As the adhesive dries, use forceps to maintain external pressure.
  • Chloramphenicol ointment may be used in a similar fashion for simple lacerations, with a small amount applied under the nail so that the ointment forms an adhesive layer as it is positioned into the nail fold.^[17]
• The proximal nail should be reinserted into the nail fold. The replaced nail keeps the nail fold open for new nail growth and provides a protective cover for the nailbed and a precise template for new nail to follow as it regenerates. It also serves as a rigid splint for any underlying fractures and reduces postoperative discomfort and improves postoperative function.
• If the original nail is missing, nonadherent gauze, aluminum suture package material, 0.020-inch reinforced silicone sheeting, acrylic (artificial) nail^[18] , or splints made from hypodermic syringes^[19] or nasogastric tubing^[20] may be used as the splint in place of the nail.
• Dress the injured finger with nonadherent gauze and 2-inch gauze roll then splint the finger.

A hand surgeon should be consulted for significantly avulsed nail matrix or for severe crush injuries.